Each year 13 million people see a doctor for chronic back pain, which is estimated to cause 2.4 million Americans to be chronically disabled. About 25 percent of people who have back pain have a herniated disk. In the US, about 450 cases of herniated disk per 100,000 require surgery such as a discectomy.
Referring to FIG. 1, a discectomy (FIG. 1(a)) is performed when the intervertebral disc 8 has herniated or torn and has not responded to a more conservative treatment. When a surgeon performs a discectomy, it is usually performed through an incision in the patient's back at a location corresponding to the problem area of the spine 2. Muscles and ligaments are moved aside to expose the offending disc 8. The surgeon then uses a variety of surgical instruments to first separate the vertebrae 4 sandwiching the disc 8, and then remove the disc 8 completely. After a discectomy is performed, the spinal column at the operation site is separated to approximate the height of the removed disc (FIG. 1b), and then an artificial disk may be placed in the separation. Spinal fixation devices (FIG. 1(c)) are used to stabilize and/or align the spine 2 during the healing process following such procedures. In some cases, clinicians fill the separation with the implantation of autologous bone to achieve fusion (fusion is illustrated in FIG. 1(d)) to restore stability of the spine 2. Alternatively, discectomy may be followed by spinal fusion, or other procedure that may be deemed necessary to strengthen and straighten the spinal canal.
Although a discectomy is frequently performed using minimally invasive devices and procedures, it is still challenging to provide the minimally invasive spine stabilization that is required following this and other spinal procedures. Improved minimally invasive spinal fixation devices and methods are required to minimizing patient risk, trauma, recovery time, and to reduce the overall costs of such procedures.